Answer:
see below
Step-by-step explanation:
butterfly = x minutes
breast = y minutes
total is 50 minutes
breast stroke = butterfly +20
Part A
x+y = 50
y = x+20
Part B
Substitute the second equation into the first
x+ (x+20) = 50
2x+20 = 50
2x+20-20 = 50-20
2x = 30
2x/2 = 30/2
x = 15
y = x+20
y = 20+15
y = 35 minutes
35 minutes on the breast stroke
Part C
45 minutes on the butterfly is not reasonable
We only have a total of 50 minutes
50-45 = 5
But he spend more time on the breast stroke ( 20 minutes more), but if he spend 45 minutes on the butterfly, he would have to spend less on the breast stroke.
It would be 10 because 6.4 is greater than 5. Correct me if i’m wrong
Answer:
n = -12
Step-by-step explanation:
(-2/3)n + 7 = 15
(-2/3)n+7-7 = 15-7 Subtract by 7 on both sides
(-2/3)n = 8 Multiply by the reciprocal of the fraction, which is
(-2/3)n*(-3/2) = 8(-3/2) This makes it so you get n *1 and isolates n.
n = -24/2 = -12
Answer: 2x+9
Explanation: 2 times a number is represented by “2x” and adding 9 is represented by “+9”
<h3>
Answer: Choice B) 468 cm^2</h3>
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Explanation:
As the diagram shows, we have a triangular face with a base of b = 18 and height of h = 13. The area of this triangular face is:
A = 0.5*b*h
A = 0.5*18*13
A = 117 square cm or cm^2
This represents the area of one face, but there are 4 identical copies of this triangular face assuming this tetrahedron is a regular polyhedron. So we have a total surface area of 4*117 = 468 cm^2 which points us to choice B
This is the amount of paint you'll need to cover the outer surface of the pyramid, or you can think of it as the amount of wrapping paper needed. This assumes there are no gaps or overlaps.
